And leonard- ii



(No Model.)

11s. PALMER & L. HQDESISLE.

AUTOMATIC ELECTRIC HEAT ALARM.

No. 475,340. Patented May 24, 1892.

UNITED STATES PATENT Orricn.

FRED SUMNER PALMER, OF BOSTON, MASSACHUSETTS, AND LEONARD lI. DESISLE, OF LAMOINE, MAINE, ASSIGNORS TO THE ELECTRIC llEAT ALARM.

COMPANY, OF BANGOR, MAINE.

AUTOMATIC ELECTRlC HEAT-ALARM.

SPECIFICATION forming part of Letters Patent No. 475,340, dated May 24, 1892.

Application filed January 9, 1892. Serial No. 417,447. (No model.)

To all whom it may concern.-

Be it known that we,FRED SUMNER PALMER, residing at Boston, in the county of Suffolk and Commonwealth of Massachusetts, and LEON- ARD H. DESISLE, residing at Lamoine, in the county of Hancock and State of Maine, citi- Zens of the United States, have invented certain new and useful Improvements in Automatic Electric Heat-Alarms and we do hereby [O declare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which it appertains to make and use the same.

Our invention consists of an automatic electric heat-alarm and is intended for use chiefly in connection with journals, bearings, and other parts of machinery Where injury may occur through overheating by reason of friction or other causes, it being designed auto- 2o matically to give an alarm when the heating of the parts begins to be so great as probably to cause damage.

It is fully illustrated in the accompanying drawings, in which- Figure 1 is a vertical section. Fig. 2 is a plan.

Fig. 3 is an elevation of the whole device.

Similar letters refer to corresponding parts throughout the figures.

e provide a thin metallic cup or reservoir 0 A. A plug B, constructed of some material which is a non-conductor of electricity, preterably hard rubber, vulcanite, or laminated fiber, is fitted or screwed into said reservoir. From the center of the plug B is a down- 3 5 wardly-extending thermometric tube I), reaching nearly to the bottom of the reservoir A, and the upper portion of the plug B is centrally and vertically bored to receive a conductor-wire or spindle C, the spindle being vertically adjustable in said plug by means of a nut F or other suitable device. The plug B is also bored vertically near its outer edge to receive a second conductor-wire-or spindle D, the lower end of which extends nearly to the bottom of the reservoir A. The spindle O is connected at its upper end with one of the poles of an electric battery by means of the set-screw E and the spindle D with the other pole of the battery by any convenient 5o device.

In operation the reservoir A is partially filled with mercury, the plug B and reservoir A are fitted together, and the whole device set in or upon the journal-box or bearing of the machine. As the parts become heated, the mercury expands and rises in the tube 1) until it comes in contact with the spindle C, and having been always in contact with the spindle D an electric circuit is thus completed and an alarm is given by means of a bell or other device. The spindle C, being vertically adjustable in the plug B, may be so set as to be broughtin contact with the mercury at any desired temperature.

Our device is constructed upon the general principle of the invention of M. S. Pierce, 0. C. Oliver, and Leonard H. Desisle, for which Letters Patent were issued January 12, 1892, and is designed to overcome a possible practical clilficulty in the operation thereof.

Our improvement, for which alone we make application for Letters Patent, (hereby expressly disclaiming the special features claimed and allowed to said Pierce, Desislo, and Oliver,) consists in making the entire plug B of material which is not a conductor of electricity, and in using the spindle D,cxtending downwardly through the plug B to the reservoir A, as one of the battery connec' tions, instead of using a metallic plug and making direct connection with such plug.

The principal advantage of our improve ment lies in the fact that with the metallic plug and thermometric tube it is found in practice that globules of the mercury may, under certain conditions, as by sudden jars, be thrown upward into the metallic tube and chamber of Pierce, Desisle, and Oliver, and be left in contact with the spindle, thus making an electric connection and giving an alarm needlessly, whereas with our device no alarm is given under the same circumstances, because the whole plug and tube are of nonconducting material and no electric connection is established.

The use of the plug constructed entirelyof non-conducting material also simplifies and cheapens the construction and cost of construction of the device, as it obviates the necessity of the special. insulation of the spindle O, which is required when the metallic plug is employed. It is obvious that the use of our spindle D becomes necessary as a consequence of the adoption of the non-conducting plug.

Having thus described our invention, what We claim, and desire to secure by Letters Patent, is-

An automatic electric heat-alarm consisting of the combination of a hollow metallic reservoir, a quantity of mercury within said reservoir, a plug, constructed of material which is a non-conductor of electricity partially fillin g said reservoir and having a small downwardly-extending tubular bore, a conductorwire or spindle supported within and sur- 

